APPENDIX: TEST FACILITIES AND INSTRUMENTATION 

 Environmental Test Facilities 



The environmental test facilities used to perform the test are shown in 

 figures Al through A4. 



The vibrator (figs. Al and A2) was designed to vibrate a maximum load 

 of 1000 pounds at a maximum acceleration level of 10 g. 



The table top of the vibrator may be rotated 90°, without the removal and 

 remounting of the test specimens, to permit horizontal vibration in either the fore- 

 and-aft or lateral axis. Vibration in the vertical axis is accomplished by posi- 

 tioning two phase-locking pins at the rear of the vibrator. Acceleration levels of 

 the vibrator table are maintained within ±5 percent of the set g level over a fre- 

 quency range of 14 to 60 Hz by a closed-loop feedback system. 



The vibrator may be withdrawn from beneath the chamber to facilitate the 

 accessibility and installation of large test specimens. The vibrator can be re- 

 motely operated in two different modes; namely, constant amplitude with variable 

 acceleration, and constant acceleration with variable amplitude. Automatic 

 changeover from constant acceleration to constant amplitude is accomplished at 

 any desired frequency by presetting the upper and lower transition points on the 

 vibrator control panel. The vibrator has built-in safety factors that enable it to 

 be operated unattended for long periods of time. 



Temperature and humidity are controlled by the two racks of instrumenta- 

 tion and controls on the right of the environmental chamber (fig. A2). 



The control console (fig. A3) consists of the vibrator control panel, six 

 channels of acceleration readout, and a multichannel oscilloscope for simulta- 

 neous display of acceleration, velocity, and displacement. 



Test Instrumentation 



The test instrumentation shown in figure A4 was used to operate and 

 monitor the performance of the test specimens. The instrumentation consisted of 

 a potentiometer pyrometer which was used to monitor the internal temperatures of 

 the test specimens , one rack of excitation and control equipment, one rack of 

 readout and monitoring equipment, and an electric counter. 



A block diagram of the instrumentation is shown in figure A5. 



19 



